Regional gain control for segmented thin-film acoustic imaging systems

Abstract

An acoustic imaging system coupled to an acoustic imaging medium to define an imaging surface. The acoustic imaging system includes an array of piezoelectric acoustic transducers formed at least in part from a thin-film piezoelectric material, such as PVDF. The array is coupled to the acoustic imaging medium opposite the imaging surface and formed using a thin-film manufacturing process over an application-specific integrated circuit that, in turn, is configured to leverage the array of piezoelectric actuators to generate an image of an object at least partially wetting to the imaging surface.

What is claimed is: 
     
       1. An acoustic imaging system comprising:
 an array of acoustic transducers; 
 an integrated circuit formed below the array of acoustic transducers and comprising:
 a first amplifier stage configured to receive a voltage signal from at least one acoustic transducer of the array of acoustic transducers; 
 a band pass filter stage to receive a first amplified output of the first amplifier stage; 
 a rectifier stage to receive a filtered output of the band pass filter stage; 
 an integrator stage to receive a rectified output of the rectifier stage; and 
 a second amplifier stage configured to receive an integrated offset output of the integrator stage; and 
 an analog to digital converter configured to receive a second amplified output of the second amplifier stage, the analog to digital converter stage configured to output a digital value corresponding to the voltage signal; and 
 
 a regional gain controller conductively coupled to at least one of the first amplifier or the second amplifier and configured to adjust a gain profile of at least one of the first amplifier or the second amplifier based at least in part on a location within the array of acoustic transducers of the at least one acoustic transducer. 
 
     
     
       2. The acoustic imaging system of  claim 1 , wherein the regional gain controller is configured to adjust the gain profile of at least one of the first amplifier or the second amplifier in response to a determination that the at least one acoustic transducer is within a defined region of the array of acoustic transducers. 
     
     
       3. The acoustic imaging system of  claim 1 , wherein the regional gain controller is configured to retrieve the gain profile from a database in communication with the regional gain controller. 
     
     
       4. The acoustic imaging system of  claim 3 , wherein the regional gain controller comprises the database. 
     
     
       5. The acoustic imaging system of  claim 1 , wherein the array of acoustic transducers is defined by:
 a thin-film piezoelectric layer; 
 a first electrode layer defining a first array of electrodes formed below the thin-film piezoelectric layer; and 
 a second electrode layer defining a second array of electrodes formed below the thin-film piezoelectric layer. 
 
     
     
       6. The acoustic imaging system of  claim 5 , wherein the thin-film piezoelectric layer is formed from PVDF. 
     
     
       7. The acoustic imaging system of  claim 6 , wherein the thin-film piezoelectric layer is formed, at least in part, from TrFE. 
     
     
       8. The acoustic imaging system of  claim 5 , wherein the thin-film piezoelectric layer is a monolithic layer. 
     
     
       9. An acoustic imaging system comprising:
 an array of acoustic transducers arranged as a set of tiles, each respective tile comprising an analog front end comprising a first amplifier stage configured to amplify a first voltage signal output by at least one acoustic transducer of the respective tile; 
 an integrated circuit coupled to each analog front end of each tile and comprising a regional gain controller and a second amplifier stage, the second amplifier stage configured to amplify a second voltage signal output by at least one analog front end; and 
 an analog to digital converter coupled to the integrated circuit and configured to sample and convert a third voltage signal output by the integrated circuit to a digital domain signal; wherein:
 the regional gain controller is configured to adjust a gain profile of at least one of the first amplifier, the second amplifier, or the analog to digital converter based at least in part on a location within the array of acoustic transducers of an acoustic transducer that generated the first voltage signal. 
 
 
     
     
       10. The acoustic imaging system of  claim 9 , wherein the regional gain controller is configured to adjust a first gain profile of the first amplifier and a second gain profile of the second amplifier. 
     
     
       11. The acoustic imaging system of  claim 9 , wherein the regional gain controller is configured to adjust the gain profile in response to feedback received form the integrated circuit. 
     
     
       12. The acoustic imaging system of  claim 9 , wherein at least one acoustic transducer of the array of acoustic transducers comprises a thin-film piezoelectric material. 
     
     
       13. The acoustic imaging system of  claim 12 , wherein the thin-film piezoelectric material comprises PVDF. 
     
     
       14. A method of signal processing in an acoustic imaging system, the method comprising:
 receiving a voltage signal from an acoustic transducer within a defined region of an array of acoustic transducers of the acoustic imaging system; 
 amplifying the voltage signal with a first amplifier configured according to a first gain profile selected in part based on a location of the acoustic transducer to output an amplified voltage signal; 
 filtering the amplified voltage signal through a bandpass filter to output a filtered signal; 
 rectifying the filtered signal to output a rippled voltage signal; 
 integrating the rippled voltage signal to output an integrated signal; 
 amplifying the integrated signal with a second amplifier configured according to a second gain profile selected in part based on the location of the acoustic transducer to output an analog signal; and 
 converting the analog signal into a digital signal with an analog to digital converter. 
 
     
     
       15. The method of  claim 14 , wherein converting the analog signal into the digital signal is performed by an analog to digital converter configured according to a third gain profile selected in part based on the location of the acoustic transducer. 
     
     
       16. The method of  claim 14 , wherein the first gain profile is selected in part based on the defined region. 
     
     
       17. The method of  claim 14 , wherein the first gain profile and the second gain profile are selected in part based on the defined region.